Our approach to comparing results in chronically infected NSG mice with results in an IFN-γ KO mouse model of acute cryptosporidiosis suggests that the NSG mouse model of chronic infection sets a more-stringent standard than acute models, since MMV665917 was highly efficacious in both models, but several compounds with good efficacy in an IFN-γ KO mouse model of acute infection (i.e., clofazimine and paromomycin) were ineffective in NSG mice (data not shown). This evidence concerns the gene IFNG and cryptosporidiosis.